Effect of SNR of input signal on the accuracy of a ratiometric wavelength measurement system

The impact of a change in signal-to-noise ratio (SNR) of the input signal on the accuracy of a ratiometric wavelength measurement system is studied. The variation of the output ratio of the system due to the change in SNR of the input signal is modeled and the experimental investigation has been carried out, and both indicate that the accuracy is influenced significantly by variations in the SNR of the input signal. The demonstration example shows a wavelength shift of 0.055 nm when the SNR of the input signal varies from 47 dB to 42 dB (the measurable range is from 1500 nm to 1600 nm and the edge filter used has a slope of 0.15 dB/nm).